1. Field of the Invention
The present disclosure relates to a data relay apparatus for communication module, and more particularly to a data relay apparatus for communication module, whereby a plurality of normally operative communication modules can perform data communication thereamong by allowing a data relay unit to relay data received by an input/output (I/O) port of an inoperative communication module in a case there is available an inoperative communication module among the plurality of communication modules, in a network configured by connecting the plurality of communication modules having two I/O Ethernet communication ports connected via a line topology.
2. Description of the Related Art
Generally, a factory automation (FA) system uses an operating method of directly accommodating different application requiring different numbers and types of input/output (I/O) circuits.
Recently, a plurality of devices is connected thereamong for communication via a network for reasons of development of communication technology, convenience of accommodation and cost reduction.
In the networks, a plurality of devices is known to be configured via a general-purpose network such as Ethernet (registered trademark, hereinafter omitted) as a communication module.
The Ethernet is the most widespread technology increasingly used in industrial manufacturing for data exchange between work stations and between office networks due to advantages of high data transmission rates (real time capability of data transmission), popularity/affinity with media, and a relatively low installation cost compared with that of field bus communication module.
Furthermore, the Ethernet disposed with two input/output (I/O) ports is also focused with advantages such as an embedded switching function capable of serially connecting each communication module to help solve a disadvantage of star topology in which failure of a centralized switch stops the entire networks.
In a case a network is configured with a line topology using the Ethernet as communication module, and if any one communication module located in midsection of the network becomes inoperative, the inoperative communication module cannot relay received data to disable normally operating communication modules to perform the data communication, unlike the conventional field bus communication module method.
Therefore, there is a need of relaying received data via the two I/O ports, even if one communication module becomes inoperative, for maintaining the strong point of Ethernet communication module mounted with two I/O ports having the abovementioned switching function and the strong point of the conventional field bus topology configuration.